Quine, Willard Van Orman

Just as the
introduction of the
irrational numbers
... is a convenient
myth [which]
simplifies the laws
of arithmetic ... so
physical objects are
postulated entities
which round out and
simplify our account
of the flux of
existence .... The
conceptional scheme
of physical objects
is [likewise] a
convenient myth,
simpler than the
literal truth and
yet containing that
literal truth as a
scattered part.